存储过程中避免抛出无数据的异常的写法

在存储过程中使用select into赋值的时候，假如无数据的话，会抛出ORA-01403异常，解决办法如下：

    BEGIN
      SELECT ROUND(TO_NUMBER(T.SINGLE_SOURCE_AMOUNT) /
                   TO_NUMBER(T.TOTAL_AMOUNT),
                   2) * 100
        INTO VAR_SINGLE_AMOUNT_PER
        FROM CS_PURCHASE_AMOUNT_YEAR T
       WHERE TO_NUMBER(T.TOTAL_AMOUNT) != 0
         AND T.TOTAL_AMOUNT IS NOT NULL
         AND T.CREATE_YEAR = VAR_LAST_YEAR
         AND T.SUPPLIER_CODE = VAR_SUPPLIER_CODE;
    EXCEPTION
      WHEN NO_DATA_FOUND THEN
        VAR_SINGLE_AMOUNT_PER := 0;
    END;